print "Hello World."

# key: deviceID name
# value: (Currently NOT USED)
deviceIDNameDict = {}

# change your file name and path
inputFileName = "/home/vgc/wei/eventName.csv"
inputFileHandler = open(inputFileName,"r")
inputFileHandler.readline() # ignore the headline
for line in inputFileHandler.readlines():
    lineElements = line.strip().split(",") # separate the line by ","
    currentDeveceIDName = lineElements[0]
    if currentDeveceIDName not in deviceIDNameDict:
        deviceIDNameDict[currentDeveceIDName] = 1
print "# of users:",len(deviceIDNameDict) # output you how many users are there
# print deviceIDNameDict
inputFileHandler.close()